By Duncan Steel 21/05/2019


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The scar on the lunar surface produced when the Israeli space probe ‘Beresheet’ slammed into the Moon on April 11 has just been spotted using an orbiting NASA satellite. 

Three nations have so far landed spacecraft on the Moon: the USA, the Soviet Union/Russia, and China. A fourth nation, Israel, has attempted to join this club, but its probe (named Beresheet) made a hard rather than a soft landing six weeks ago. Now detailed images of the lunar surface obtained using NASA’s Lunar Reconnaissance Orbiter (LRO) have been scoured and the crash site identified.

Beresheet (Hebrew for ‘In the beginning’, the first words in the biblical Book of Genesis) was built and operated by Israel Aerospace Industries on behalf of SpaceIL, a non-profit organisation founded in 2011 with the specific aim of landing a probe on the Moon. The plan was for this small (150 kg — about the size of a washing machine) probe to land gently on the Moon and return scientific data, but a gyroscope failure during the final approach stage led to it crashing into the lunar surface at around one kilometre per second.

Path taken by the Beresheet probe from Earth to Moon. It all worked well, until the very last minutes.

At such a speed it would be expected that a small crater would be excavated, and so imagery obtained by LRO was examined to see if this could be found. Using the LRO camera systems several new craters formed by the impact of tiny asteroids/large meteoroids have been detected in LRO imagery since that satellite was inserted into lunar orbit in 2009. Three deliberate impacts by US satellites (GRAIL-A, GRAIL-B and LADEE) have also had their crash zones identified, and the LRO imagery is of such high resolution that the paths traversed by the Apollo astronauts can also be spotted; for example, see the pictures here of the Apollo 17 landing site. (New images from LRO can be found here.)

Finding a new scar on the Moon’s surface is not easy when you are not sure precisely where it is, and also LRO takes some weeks to cover the whole of the Moon. As it happens an image obtained on April 22, eleven days after Beresheet crashed, contains the end-point of that probe, and its identification has recently been announced. Here are before (from 30 months ago) and after (post-April 11) images of the area:

Lunar Reconnaissance Orbiter Camera images of the impact region of Beresheet, before and after its hypervelocity arrival. (Courtesy NASA/Arizona State University.)

The new dark ‘hole’ where the high-speed spacecraft punched through the regolith to expose covered material is clear, along with a lighter ‘halo’ of ejected material (and also doubtless parts of the satellite and fuel/oxidiser). A streak apparent at an azimuthal angle of about 200 degrees in the ‘After’ image may be due to the impact occurring at a very low angle (less than 10 degrees away from the horizontal).

The way it should have been: artist’s impression of the Beresheet probe safely landed on the lunar surface.

If at first you don’t succeed…  The reality is that space exploration is difficult, and the path to eventual success is littered with failures. A follow-up mission with the same aim (landing on the Moon) was quickly announced: Beresheet-2.

 


 

Addendum 28 May: It seems that a new impact crater formed by a small asteroid/large meteoroid may be mapped soon by the LRO. During the total lunar eclipse on 21st January this year, a Spanish observing team that regularly monitors the lunar surface for impacts using a ground-based telescope detected just such an event, estimated to involve the release of energy equivalent to 1.5 tonnes of TNT, and may have excavated a crater 10 to 15 metres across… large enough to be picked up by the LRO camera. A video of the event is available here, while the full story is covered here. Another YouTube video clip that incorporates the detection and gives background information is available here; this was produced by my old friend Scott Manley, who was responsible for some of the artwork in my book Target Earth.